Peripheral nerve stimulation for restless legs syndrome

Abstract

Systems and methods for treating a patient having symptoms of restless legs syndrome (RLS) or Periodic Limb Movement Disorder (PLMD) using high-frequency stimulation by applying a high-frequency pulsed electrostimulation therapy signal to a femoral nerve or a branch thereof. An electrostimulation device can include or use clonus detection circuitry can be used such as to monitor for a presence of clonic activity during treatment. Feedback from the clonus detection circuitry can be used to select or modify a therapy parameter of the electrostimulation device such as to help mitigate clonic muscle activity during therapy.

What is claimed is: 
     
         1 . A transcutaneous neurostimulation therapy device for treating a patient having one or more symptoms associated with at least one of Restless Legs Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD) using applied high-frequency electrostimulation, the device comprising:
 an electrostimulation electronics unit including first and second skin electrodes for delivering an electrostimulation therapy signal to the patient at an external target body location, wherein the electrostimulation therapy signal is delivered at least a frequency of between 500 and 10,000 Hz and at a current of between 5 and 50 mA; and   clonus detection circuitry configured select a therapy parameter of the device based on data corresponding with clonic muscle activity from the patient.   
     
     
         2 . The device of  claim 1 , wherein the clonus detection circuitry is configured to determine a target distance between the first and second skin electrodes based on the data corresponding with clonic muscle activity from the patient. 
     
     
         3 . The device of  claim 1 , wherein the clonus detection circuitry is configured to determine a target compression applied by a compression band to the external target body location, the target compression determined based on the data corresponding with clonic muscle activity from the patient. 
     
     
         4 . The device of  claim 1 , wherein the clonus detection circuitry is configured to modulate a parameter of the electrostimulation signal delivered by the first and second skin electrodes, the modulation based on the data corresponding with clonic muscle activity from the patient. 
     
     
         5 . The device of  claim 1 , further comprising at least one EMG sensing electrode for inspecting at least one muscle innervated by the femoral nerve for clonic muscle activity and providing the data corresponding therewith. 
     
     
         6 . The device of  claim 1 , further comprising a garment configured to provide compression to at least a portion of the leg of the patient including the at least one muscle innervated by the at least a branch of the femoral nerve. 
     
     
         7 . The device of  claim 6 , wherein the level of compression provided by the garment is adjustable. 
     
     
         8 . The device of  claim 7 , wherein the clonus detection circuitry is configured to determine a target level of compression of the garment based on data corresponding with clonic muscle activity from the patient. 
     
     
         9 . The device of  claim 1 , wherein the clonus detection circuitry is configured to determine a target frequency or a target current of the at least the electrostimulation therapy signal based on data corresponding with clonic muscle activity from the patient. 
     
     
         10 . The device of  claim 1 , wherein the first and second skin electrodes are selectable from a plurality of electrodes in an electrode grid. 
     
     
         11 . The device of  claim 10 , wherein the clonus detection circuitry is configured to select between electrodes in the electrode grid based on data corresponding with clonic muscle activity from the patient. 
     
     
         12 . A method of treating a patient having one or more symptoms associated with at least one of Restless Legs Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD) using applied high-frequency electrostimulation, the method comprising:
 providing at least one first electrostimulation electrode for coupling to at least a first external target body location of the patient proximate to at least a first branch of the femoral nerve including at least one of a branch innervating the rectus femoris muscle, a branch innervating the vastus medialis muscle, a branch innervating the vastus lateralis muscle, or a branch innervating the vastus intermedius muscle; and   delivering at least a first high-frequency AC electrostimulation therapy signal to the at least one first external target body location using the at least one electrostimulation electrode, wherein the at least a first electrostimulation therapy signal is defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 5 and 50 mA.   
     
     
         13 . The method of  claim 12 , wherein delivering at least a first high-frequency AC electrostimulation therapy signal further comprises delivering an electrostimulation therapy signal that is above a tonic motor threshold. 
     
     
         14 . The method of  claim 12 , wherein delivering at least a first high-frequency AC electrostimulation therapy signal further comprises delivering an electrostimulation therapy signal that is below a pain threshold. 
     
     
         15 . The method of  claim 12 , wherein coupling at least one first electrostimulation electrode to at least a first external target body location comprises:
 providing at least one first electrostimulation electrode for coupling to a first external target location of the patient proximate to a first branch of the femoral nerve including at least one of a branch innervating the rectus femoris muscle, a branch innervating the vastus medialis muscle, a branch innervating the vastus lateralis muscle, or a branch innervating the vastus intermedius muscle; and   providing at least one second electrostimulation electrode for coupling to a second external target location of the patient proximate to a second branch of the femoral nerve different from the first branch and including at least one of a branch innervating the rectus femoris muscle, a branch innervating the vastus medialis muscle, a branch innervating the vastus lateralis muscle, or a branch innervating the vastus intermedius muscle; and wherein delivering at least a first high-frequency AC electrostimulation therapy signal to the at least one first external target body location comprises:   delivering a first high-frequency AC electrostimulation therapy signal to the first external target location, wherein the first high-frequency electrostimulation therapy signal is defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 5 and 50 mA; and   delivering a second high-frequency AC electrostimulation therapy signal to the second external target location, wherein the second high-frequency electrostimulation therapy signal is defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 5 and 50 mA.   
     
     
         16 . The method of  claim 15 , further comprising:
 performing at least one action to minimize clonic muscle activity in the at least one muscle innervated by the first branch of the femoral nerve and in the at least one muscle innervated by the second branch of the femoral nerve, wherein the at least one action is selected from   selecting at least one of the first external target location and second external target location so minimize said clonic muscle activity; and   selecting a distance between the first external target location and the second external target location to minimize said clonic muscle activity.   
     
     
         17 . The method of  claim 16 , further comprising:
 locating at least one EMG sensing electrode on the skin of the patient proximate to the at least one muscle innervated by the at least a first branch of the femoral nerve;   delivering an electrostimulation test signal to the at least one first electrostimulation electrode, wherein the electrostimulation test signal is defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 0 and 50 mA;   sensing EMG activity of the at least one muscle innervated by the at least a first branch of the femoral nerve evoked by the electrostimulation test signal; and   detecting clonic muscle activity corresponding with the EMG activity; and   
       wherein performing at least one action to minimize clonic muscle activity involves selecting the target locations or the distance therebetween based on the detected clonic muscle activity corresponding with the EMG activity. 
     
     
         18 . The method of  claim 12 , wherein coupling at least one first electrostimulation electrode to at least a first external target body location comprises:
 providing a first plurality of electrostimulation electrodes for coupling to a first plurality of external target locations proximate to a first branch of the femoral nerve including at least one of a branch innervating the rectus femoris muscle, a branch innervating the vastus medialis muscle, a branch innervating the vastus lateralis muscle, or a branch innervating the vastus intermedius muscle; and   providing a second plurality of electrostimulation electrodes for coupling to a second plurality of external target locations proximate to a second branch of the femoral nerve different from the first branch and including at least one of a branch innervating the rectus femoris muscle, a branch innervating the vastus medialis muscle, a branch innervating the vastus lateralis muscle, or a branch innervating the vastus intermedius muscle; and   
       wherein delivering at least a first high-frequency AC electrostimulation therapy signal to the at least one first external target body location comprises:
 delivering a first high-frequency AC electrostimulation therapy signal to one or more of the first plurality of electrostimulation electrodes, wherein the first high-frequency electrostimulation therapy signal is defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 5 and 50 mA; and 
 delivering a second high-frequency AC electrostimulation therapy signal to one or more of the second plurality of electrostimulation electrodes, wherein the second high-frequency electrostimulation therapy signal is defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 5 and 50 mA. 
 
     
     
         19 . The method of  claim 18 , further comprising:
 performing at least one action to minimize clonic muscle activity in the at least one muscle innervated by the first branch of the femoral nerve and in the at least one muscle innervated by the second branch of the femoral nerve, wherein the at least one action is selected from   selecting at least one of the first external target location and second external target location so minimize said clonic muscle activity; and   selecting a distance between the first external target location and the second external target location to minimize said clonic muscle activity.   
     
     
         20 . The method of  claim 12 , further comprising:
 performing at least one action to minimize clonic muscle activity in the at least one muscle innervated by the at least a first branch of the femoral nerve, wherein the at least one action is selected from:
 providing compression to at least a portion of the leg of the patient including the at least one muscle innervated by the at least a first branch of the femoral nerve; 
 selecting at least one of the frequency and the current of the at least a first high-frequency AC electrostimulation therapy signal to minimize myoclonic muscle twitches or jerks in the at least one muscle innervated by the at least a first branch of the femoral nerve. 
   
     
     
         21 . The method of  claim 12 , wherein electrostimulation therapy signal is below at least one of a tolerability threshold and a distraction threshold. 
     
     
         22 . The method of  claim 21 , wherein the distraction threshold is a threshold of the maximum stimulation at which a patient is not distracted from falling asleep during a sleep period. 
     
     
         23 . The method of  claim 12 , wherein delivering the at least a first high-frequency AC electrostimulation therapy signal comprises applying charge-balanced AC controlled-current to the at least one first external target body location, and controlling or adjusting the current based on a measured load impedance or component thereof. 
     
     
         24 . The method of  claim 12 , further comprising:
 locating at least one EMG sensing electrode on the skin of the patient proximate to the at least one muscle innervated by the at least a first branch of the femoral nerve;   delivering an electrostimulation test signal to the at least one first electrostimulation electrode, wherein the electrostimulation test signal is defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 0 and 50 mA;   sensing EMG activity of the at least one muscle innervated by the at least a first branch of the femoral nerve evoked by the electrostimulation test signal;   determining whether or not the electrostimulation test signal is above a sensory threshold and below a pain threshold;   repeating the steps of delivering an electrostimulation test signal, sensing EMG activity and determining whether or not the electrostimulation test signal is above the sensory threshold and below the pain threshold, wherein the electrostimulation test signal for each repetition of delivering an electrostimulation test signal have at least one of a different frequency and a different current than an immediately preceding electrostimulation test signal; and   selecting one of the electrostimulation test signals as the first high-frequency AC electrostimulation therapy signal.   
     
     
         25 . The method of  claim 24 , wherein delivering an electrostimulation test signal comprises delivering a first electrostimulation test signal having a first current value, and wherein each repeated step of delivering an electrostimulation test signal comprises applying an electrostimulation signal having a current higher than the current of the immediately preceding electrostimulation test signal. 
     
     
         26 . The method of  claim 25 , wherein the repeated steps of delivering an electrostimulation test signal comprise applying a series in electrostimulation test signals for which the current value of the test signals increases at a rate of from 1 mA/0.25 seconds to 1 mA/15 seconds. 
     
     
         27 . The method of  claim 12 , further comprising:
 monitoring at least one body parameter selected from a body movement, a cardiac parameter, a respiratory parameter, and a neurological parameter;   determining whether the patient is in a sleep state or a waking state;   if the patient is in a sleep state   processing the at least one body parameter; and   adjusting the electrostimulation therapy signal if the body parameter is indicative of one of arousal or a likelihood of impending arousal.   
     
     
         28 . The method of  claim 12 , wherein coupling at least one first electrostimulation electrode to at least a first external target body location comprises:
 coupling at least one first electrostimulation electrode to at least a first external target body location on a left leg of the patient proximate to at least a first branch of the left femoral nerve selected from a branch innervating the rectus femoris muscle, a branch innervating the vastus medialis muscle, a branch innervating the vastus lateralis muscle, and a branch innervating the vastus intermedius muscle; and   coupling at least one second electrostimulation electrode to at least a second external target body location on a right leg of the patient proximate to at least a first branch of the right femoral nerve selected from a branch innervating the rectus femoris muscle, a branch innervating the vastus medialis muscle, a branch innervating the vastus lateralis muscle, and a branch innervating the vastus intermedius muscle;   
       and wherein delivering at least a first high-frequency AC electrostimulation therapy signal comprises delivering a first electrostimulation therapy signal having a frequency of between 500 and 10,000 Hz and a current of between 5 and 50 mA to the at least a first external target body location using the at least one first electrostimulation electrode, the first electrostimulation therapy signal being above a sensory threshold and below a pain threshold, the method further comprising:
 delivering a second electrostimulation therapy signal having a frequency of between 500 and 10,000 Hz and a current of between 5 and 50 mA to the at least a second external target body location using the at least one second electrostimulation electrode, the second electrostimulation therapy signal being above a sensory threshold and below a paid threshold. 
 
     
     
         29 . A method of treating a patient having one or more symptoms associated with at least one of Restless Legs Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD) using applied high-frequency electrostimulation, the method comprising:
 providing at least one first electrostimulation electrode for coupling to a first external target location of the patient proximate to a first branch of the femoral nerve including at least one of a branch innervating one of the rectus femoris muscle, the vastus medialis muscle, the vastus lateralis muscle, or the vastus intermedius muscle;   providing at least one second electrostimulation electrode for coupling to a second external target location of the patient proximate to a second branch of the femoral nerve different from the first branch and including at least one of a branch innervating one of the rectus femoris muscle, the vastus medialis muscle, the vastus lateralis muscle, or the vastus intermedius muscle;   delivering a first high-frequency AC electrostimulation therapy signal to the first external target location, wherein the first high-frequency electrostimulation therapy signal are defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 5 and 50 mA;   delivering a second high-frequency AC electrostimulation therapy signal to the second external target location, wherein the second high-frequency electrostimulation therapy signal is defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 5 and 50 mA; and   performing at least one action to minimize clonic muscle activity in the at least one muscle innervated by the first branch of the femoral nerve and in the at least one muscle innervated by the second branch of the femoral nerve, wherein the at least one action is selected from   selecting at least one of the first external target location and second external target location to minimize said clonic muscle activity; and   selecting a distance between the first external target location and the second external target location to minimize said clonic muscle activity.   
     
     
         30 . A method of treating a patient having one or more symptoms associated with at least one of Restless Legs Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD) using applied high-frequency electrostimulation, the method comprising:
 providing at least one first electrostimulation electrode for coupling to at least a first external target body location of the patient proximate to at least a first branch of the femoral nerve including at least one of the rectus femoris, the vastus medialis, the vastus lateralis or the vastus intermedius;   delivering at least a first high-frequency AC electrostimulation therapy signal to the at least one first external target body location using the at least one electrostimulation electrode, wherein the at least a first electrostimulation therapy signal is defined by a plurality of parameters including at least a frequency of between 500 and 10,000 Hz, and a current of between 5 and 50 mA; and   performing at least one action to minimize clonic muscle activity in the at least one muscle innervated by the at least a first branch of the femoral nerve, wherein the at least one action is selected from:
 providing compression to at least a portion of the leg of the patient including the at least one muscle innervated by the at least a first branch of the femoral nerve; and 
 selecting at least one of the frequency and the current of the at least a first high-frequency AC electrostimulation therapy signal to minimize myoclonic muscle twitches or jerks in the at least one muscle innervated by the at least a first branch of the femoral nerve.